熔盐法合成高导热磷化硼及其热管理性能研究

随着电力电子器件封装密度提高, 开发导热性能优异的热界面材料受到了广泛关注。绝大多数传统导热填料的热导率较低, 因此合成新型高导热填料是提高热界面材料导热性能的重要途径。本研究通过简单的熔盐法合成了高导热的磷化硼(BP)颗粒, 与氮化硼(h-BN)混合并通过搅拌和浇注的方法填充到环氧树脂(EP)基体中制备得到树脂基复合材料(BP-BN/EP)。实验结果表明：采用三盐法(NaCl : KCl : LiCl)合成的BP产率最高达到74%, 相对于单盐法(41%)和双盐法(39%)分别提高了33%和35%。对于BP-BN/EP复合材料, 复合材料的微结构显示BP和BN颗粒均匀分布在环氧树脂基体。当混合填料体积分数为30%时, 该复合材料的热导率达到1.81 W?m^-1?K^-1, 是纯树脂热导率(0.21 W?m^-1?K^-1)的8.6倍, 这与BP颗粒作为桥梁连接相邻BN颗粒形成导热网络有关。除此以外, 相较于不含BP的复合材料(SBN-BN/EP), BP-BN/EP复合材料展现出更加优异的热导率、热稳定性和较好的热力学性能。因此, 熔盐法合成的BP在热管理领域具有较大的应用前景。

Boron Phosphide with High Thermal Conductivity: Synthesis by Molten Salt Method and Thermal Management Performance

With the increase of packaging density of power electronic devices, the development of thermal interface materials with excellent thermal conductivity has received widely spread attention. Due to most traditional heat conductors showing relatively low thermal conductivity, synthesis of new high thermal conductive fillers is an important way to improve the thermal conductivity of thermal interface materials. In this study, boron phosphide (BP) particles were synthesized by a facile molten salt method, then mixed with boron nitride (h-BN) and filled into epoxy resin (EP) to prepare epoxy resin matrix composites (BP-BN/EP) by stirring and casting. With the three salts (NaCl : KCl : LiCl) method, the experimental data showed that the highest yield of BP reached 74%, 33% and 35% higher than that of the single salt method (41%) and the double salt method (39%), respectively. In the BP-BN/EP composites, BP and BN particles were uniformly dispersed in the EP matrix. When the hybrid filler loading at 30% (in volume), the thermal conductivity reached 1.81 W·m^-1·K^-1, 8.6 times of that of pure epoxy (0.21 W·m^-1·K^-1). The thermal conductivity improvement was related to the construction of thermal conductive network by BP particles linking adjacent BN sheets. In addition, to excellent thermal conductivity, the BP-BN/EP composites also showed good thermal stability and good thermodynamic properties. Therefore, the synthesized BP by molten salt method has great application prospects in the field of heat management.